Does anyone have experience in working with yellow and black striped olive beetles? I am working to resurrect an olive grove in South Africa that is infested with them, and my intention is to manage it organically. Have started pruning and spraying neem-oil. It's helping a bit but the beetles are still around. I will be focusing on building up the soil health and nutrition for the trees in the coming months/years, but what should I spray in the meantime that could help??
Doing a little research on how to encourage the, yes the compost is a good start. They also like minimal soil disturbance, which I suspect is ideal management in an orchard. Based on my own experience here, you will also need to keep the soil evenly moist and preferable sheltered from direct sunlight with a mulch or plant cover.
My soils here dry out through most of the yard each summer because I've refused to water grass during our summer drought. Because of that, I've been spraying nematodes at the start of the wet season each year, but can't maintain a healthy population. Even the short time they survive in my yard makes a big difference in the number of ants, grubs, and fleas we have for the rest of the year. I will be so happy if I finally improve my soils enough that I can stop spraying for these benefits. I'll know it's happened when fire ants stop coming back into the yard.